160 THE VALLEYS OF SOME OF THE IRISH LAKES. 



surface streams flowing from them, especially when 

 in the carboniferous limestone, may have had an 

 underground drainage. This is suggested by the 

 many systems of lakes connected with subterranean 

 rivers that still exist in different parts of the 

 island. We have already described those connected 

 with Coole Lough, near Gort, County Galway, and 

 we may now give a brief description of the river 

 Fergus, County Clare, from the pen of the late Mr 

 F. J. Foot, more especially as the lakes connected 

 with it are of considerable size. 



" The river Fergus rises in Lough Fergus, be- 

 tween Corrofin and Ennistimon, at an elevation of 

 about 350 feet above the sea ; flows eastward and 

 northward for two miles and a half, when it receives 

 the Clooneen river ; thence it takes an easterly course 

 for a mile and a half, when, on entering the limestone 

 ground, it suddenly disappears in a swallow-hole 

 or vertical cavity in the rock. Half a mile to the 

 east it again emerges to the light, from a cavern 

 called * Poulnaboe,' from which it flows down into 

 Inchiquin Lough, and thence into Lough Atedaun. 

 No visible river flows out of this lough, but the 

 Fergus is supposed to have a subterraneous course 

 in a direction of about E.S.E. to Dromore Lough, 

 whence it flows southward, now above and now below 

 ground, to Ennis, and thence to the Shannon." 1 



1 " Maps and Memoirs, Geological Survey," Sheets 122 and 123. 



